When BCY published breaking strengths, they gave 8125 a rating of 120# (static load, not shock).
Personally I'd go with 12 strands, with 18 in the loops. I pad my loops with dacron.
I wouldn't expect any big speed gains, but it might make a difference in noise. That's what I've heard the most about--rarely if ever a noticeable speed difference, but often it can make even a quiet bow quieter.
With 8125 you will have a more durable string that has a lot less stretch and creep than dacron also.
Chad